Varicella (Chickenpox)

Varicella, commonly known as chickenpox, is a highly contagious viral infection that causes an itchy, blister-like rash across the body. While it is usually mild in healthy children, it can lead to serious complications in certain groups, and vaccination has dramatically reduced cases by nearly 90% since the 1990s.

Table of contents

• What is varicella?
• Who gets chickenpox?
• Symptoms and stages of chickenpox
• How chickenpox spreads
• Possible complications
• Diagnosis
• Treatment
• Prevention through vaccination
• Home care tips

What is varicella?

Varicella, commonly called chickenpox, is a disease caused by the varicella-zoster virus (VZV), which belongs to the herpes virus family^[1]. This virus is the same one that causes shingles, a painful condition that can occur years later when the virus reactivates in the body^[2].

Chickenpox used to be extremely common before vaccines became available. Almost everyone got chickenpox as a child. However, since the chickenpox vaccine was introduced in 1995, the number of cases has dropped by about 97%^[19]. Despite this dramatic decrease, it is still possible to get chickenpox, especially if you are not vaccinated^[1].

The illness typically lasts about 4 to 7 days. For most healthy people, getting chickenpox once provides immunity for life, though it is possible to get it more than once in rare cases^[1]. After you recover from chickenpox, the virus stays dormant in your nerve cells and can reactivate later in life to cause shingles^[2].

Who gets chickenpox?

Anyone who has not had chickenpox or received the chickenpox vaccine can get the disease^[1]. Children are most commonly affected, though the disease can occur at any age. Before vaccines were available, it was most common in children between 3 and 6 years old^[13].

While chickenpox is generally mild in healthy children, some people face higher risks of severe illness and complications. These high-risk groups include^[1]:

• Pregnant women
• Newborn babies and infants under 1 year old
• Adolescents and adults
• People with weakened immune systems, such as those with HIV/AIDS, cancer, or those who have had transplants
• People taking medications that suppress the immune system, including chemotherapy, long-term steroids, or immunosuppressive drugs

Chickenpox can be serious, even life-threatening, in these groups^[4]. Adults account for only about 5% of reported chickenpox cases but represent approximately 35% of deaths from the disease^[9].

Symptoms and stages of chickenpox

The most recognizable symptom of chickenpox is an itchy rash that appears on the skin. However, other symptoms often appear before the rash develops. Adults may experience fever and general tiredness 1 to 2 days before the rash begins, while in children, the rash is often the first sign^[7].

Common symptoms include^[13]:

• Low-grade fever
• Feeling tired and weak
• Headache
• Loss of appetite or stomach discomfort
• An itchy rash with small blisters

The rash typically appears 10 to 21 days after exposure to the virus^[7]. It usually starts on the face, scalp, chest, and back before spreading to the rest of the body, including the arms and legs^[1]. The rash can even appear inside the mouth, on the scalp, in the armpits, and on the eyelids^[4].

The chickenpox rash goes through three distinct stages^[13]:

1. Red bumps (papules): Small raised red spots appear on the skin, resembling pimples or insect bites. This stage lasts a few days.
2. Fluid-filled blisters (vesicles): The bumps develop into thin-walled blisters filled with clear fluid. These blisters break open after about one to two days.
3. Scabs and crusts: When the blisters break, they form crusts and scabs that take several more days to heal.

A person with chickenpox may have as many as 250 to 500 blisters, though some cases have fewer^[1]. New bumps continue to appear over several days, so you may have bumps, blisters, and scabs all present on your body at the same time^[18]. It usually takes about 1 week for all of the blisters to become scabs^[1].

People who have been vaccinated against chickenpox can still get the disease, but they usually have much milder symptoms with fewer blisters, low or no fever, and a shorter illness^[5]. The rash in vaccinated people may look different and may not progress to typical blisters^[5].

How chickenpox spreads

Chickenpox is extremely contagious. The virus spreads very easily from person to person. Up to 90% of people who are not immune and have close contact with someone who has chickenpox will also get infected^[1].

The virus spreads in several ways^[1]:

• Through the air when an infected person coughs, sneezes, talks, or laughs
• Through direct contact with the fluid from chickenpox blisters
• By touching objects or surfaces contaminated with the virus

A person with chickenpox is contagious from 1 to 2 days before the rash appears until all the blisters have crusted over (formed scabs)^[1]. This means someone can spread the virus before they even know they are sick. If a vaccinated person gets chickenpox, they remain contagious until no new bumps have appeared for 24 hours, even if the bumps do not form typical crusts^[1].

It takes about 2 weeks (ranging from 10 to 21 days) after exposure to someone with chickenpox for symptoms to develop^[1]. During this incubation period, the infected person may appear completely healthy.

You can also get chickenpox from someone who has shingles. People with shingles can spread the varicella-zoster virus through direct contact with their rash or by breathing in virus particles that come from the blisters^[1]. If you have never had chickenpox and are exposed to someone with shingles, you will develop chickenpox, not shingles^[1].

Possible complications

For most healthy children, chickenpox causes only mild symptoms. However, the disease can lead to serious complications, particularly in high-risk groups^[4].

The most common complications include^[4]:

• Bacterial skin infections: Scratching the blisters can allow bacteria to enter the skin, causing infections that may require antibiotics. These infections are most common in children^[9].
• Pneumonia: Lung infection can occur, caused either by the virus itself or by bacteria. This is more common in adults^[9].
• Dehydration: Loss of fluids can occur, especially if blisters develop in the mouth and make eating and drinking difficult^[4].
• Brain inflammation (encephalitis): Though rare, the virus can infect the brain^[4].
• Cerebellar ataxia: Problems with balance and coordination^[5].

Chickenpox during pregnancy poses special risks. The virus can harm unborn children and can be life-threatening for newborn babies^[20]. Pregnant women who have never had chickenpox or been vaccinated should avoid contact with anyone who has the disease and should contact their healthcare provider immediately if they are exposed^[6].

Diagnosis

Healthcare providers can usually diagnose chickenpox by looking at the characteristic rash^[13]. The appearance of the blisters and their distribution across the body are typically distinctive enough for diagnosis.

However, because vaccination has made chickenpox less common and because some cases (especially in vaccinated people) can have an unusual appearance, laboratory testing is now increasingly recommended to confirm the diagnosis^[5].

Laboratory tests that can confirm chickenpox include^[5]:

• Polymerase chain reaction (PCR): This is the preferred method for laboratory confirmation. It is the most sensitive and provides results quickly.
• Direct fluorescent antibody assay (DFA): This test is highly specific for the virus but less sensitive than PCR.
• Viral culture: Growing the virus from a sample, though this is less sensitive than PCR.
• Blood tests: These can show antibody responses to the virus, but they may not be as reliable in vaccinated people.

Healthcare providers may take samples of fluid from the blisters or tissue from the rash and send them to a laboratory for testing^[2].

Treatment

For most healthy children and adults, chickenpox does not require specific medical treatment. The disease simply needs to run its course^[10]. Treatment focuses on managing symptoms and preventing complications.

However, certain groups of people may need antiviral medication. Healthcare providers may prescribe antiviral drugs for^[11]:

• Otherwise healthy people older than 12 years of age
• People with chronic skin or lung disease
• People taking long-term aspirin therapy or steroid therapy
• Pregnant women
• People with weakened immune systems

The most commonly used antiviral medication is acyclovir (Zovirax, Sitavig). Other options include valacyclovir (Valtrex) and famciclovir^[10]. These medications work best when started within 24 hours after the rash first appears^[11]. They can shorten the length of the illness and reduce the severity of symptoms^[14].

For people at very high risk who have been exposed to chickenpox but have not yet developed symptoms, varicella-zoster immune globulin (VariZIG) may be given. This treatment can reduce the severity of the infection if given within 10 days (ideally within 4 days) of exposure^[14].

If complications develop, such as bacterial skin infections or pneumonia, additional treatments like antibiotics may be necessary^[10].

Prevention through vaccination

The best way to prevent chickenpox is to get vaccinated^[1]. The chickenpox vaccine is very effective and has dramatically reduced the number of cases since it became available.

Vaccination recommendations include^[6]:

• Children: Two doses are recommended. The first dose should be given at 12 to 15 months of age, and the second at 4 to 6 years of age.
• Older children: Children 12 years and younger who have not received all their vaccines should get two doses at least 3 months apart.
• Teenagers and adults: People 13 years and older who have never had chickenpox or been vaccinated should get two doses 4 to 8 weeks apart.

The chickenpox vaccine should not be given during pregnancy^[6]. Women hoping to become pregnant should be vaccinated before conception if they have never had chickenpox.

Most people who get the vaccine will not get chickenpox. If a vaccinated person does develop chickenpox, it is usually very mild, with fewer than 50 blisters, low or no fever, and a shorter illness^[5]. The vaccine prevents almost all cases of severe illness^[1].

If you or someone in your family gets chickenpox, several precautions can help prevent spreading it to others^[1]:

• Stay home from school, work, or childcare until all blisters have scabbed over
• Avoid contact with people who have never had chickenpox or been vaccinated
• Avoid contact with pregnant women, newborns, and people with weakened immune systems
• Cover your mouth and nose when coughing or sneezing
• Wash your hands frequently with soap and water for at least 20 seconds

Home care tips

There are several things you can do at home to help relieve symptoms and prevent skin infections while recovering from chickenpox^[11].

To relieve itching:

• Take lukewarm baths every 3 to 4 hours. You can add colloidal oatmeal or baking soda to the bath for extra relief^[11].
• After bathing, gently pat (do not rub) the skin dry with a soft towel^[18].
• Apply calamine lotion to itchy areas. Avoid using it on the face, especially near the eyes^[18].
• Use cool, wet cloths on itchy areas^[25].
• Ask your healthcare provider about using an over-the-counter antihistamine to help with itching^[11].

To prevent scratching and skin infections:

• Keep fingernails trimmed short and clean^[11].
• Use soft mittens or gloves at bedtime to prevent scratching during sleep^[18].
• If you do scratch a blister, wash your hands immediately with soap and water for at least 20 seconds^[11].
• Try to avoid getting hot and sweaty, as this can make itching worse^[25].

For mouth sores:

• Offer cold, soft, bland foods that are easy to swallow^[18].
• Serve sugar-free popsicles to soothe mouth sores and help with fluid intake^[24].
• Encourage drinking plenty of fluids to avoid dehydration.

For fever and discomfort:

• Use non-aspirin medications such as acetaminophen (Tylenol) to reduce fever^[25].
• Never give aspirin to children or teenagers with chickenpox. Aspirin use in children with chickenpox is associated with Reye syndrome, a serious and potentially fatal condition that affects the liver and brain^[11].
• Get plenty of rest^[25].

When to contact your healthcare provider:

You should call your doctor if^[11]:

• The fever lasts longer than 4 days or rises above 102°F (38.9°C)
• Any area of the rash becomes very red, warm, tender, or begins leaking thick, discolored fluid (signs of bacterial infection)
• You or your child has difficulty breathing or a severe cough
• You or your child has difficulty walking, confusion, severe headache, or stiff neck
• You or your child is vomiting frequently or has severe abdominal pain
• The rash shows signs of bleeding or bruising

If you have been exposed to chickenpox and fall into a high-risk group (pregnant, have a weakened immune system, or have never had chickenpox or been vaccinated), contact your healthcare provider right away^[11].

chickenpox, varicella-zoster infection